Larry, Yes HF acid is very, very nasty stuff. The vapors are extraordinarliy dangerous - it makes nitric acid look like mother's milk. One would do much better to "do figure 8's" with a pencil eraser and carborundum.
At a hamfest a while ago I picked up a crystal grinding kit (from the 40's?) by the "Talkie" company. I'll scan the one paragraph instruction sheet if anyone is interested. de KA4JVY Mark --- Larry Szendrei <[EMAIL PROTECTED]> wrote: > I remember the article - I think it may have been > reproduced in "SSB for > the Radio Amateur" published by the ARRL in the 50's > or 60's. Since I > work with semiconductors, I tried moving a crystal > up by etching in > "BOE" (Buffered Oxide Etch) I had access to, several > years ago. Ihe rate > of frequency change was so slow I gave up on the > project! A more > aggressive (read more concentrated) solution would > have been faster, but > I ran out of time & patience to experiment. This > method is NOT > recommended - most of the solutions contain HF > (hydrofluoric acid), very > nasty stuff! (I'm also a chemist, BTW...) > > 73, > -Larry/NE1S > > Brian Carling wrote: > > > > On 12 Dec 2002 at 19:39, [EMAIL PROTECTED] wrote: > > > > > Along the same lines, does anyone know about > chemical etching of > > > crystals to shift frequency? I expect it > requires some nasty hazmat > > > stuff to cut the quartz. I saw a reference in an > old QST but didn't > > > have the issue mentioned. > > > > > > -Tony, K1KP > > > > I don't think chemical etching is recommended. > > > > The commercial boys do it with first a grinder to > shape the crystal "bar" and then > > a SAW, to get the slices made aproximately right. > > Of course the wafers then are actually thicker > than they will need to be in the end. > > > > The final step is to put them in a lapping machine > which rubs them down to the > > required thickness, and up to the required > frequency in a lubricative cutting paste > > slurry which combines lubricants, cutting > compounds and a means to conduct > > heat away into the lapping machine > > from the crystals so that they don't break. > > > > Of course radio amateurs have been known to use > all kinds of unconventional > > methods and perhaps that could include chemical > etching.... > > > > _______________________________________________ > > AMRadio mailing list > > [email protected] > > http://mailman.qth.net/mailman/listinfo/amradio > --------------------------------------------- > Introducing NetZero Long Distance > 1st month Free! > Sign up today at: www.netzerolongdistance.com > _______________________________________________ > AMRadio mailing list > [email protected] > http://mailman.qth.net/mailman/listinfo/amradio __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com
